Field of the Invention
The invention relates to an electronic device, and more particularly to guard traces of a printed circuit board (PCB) in an electronic device arranged by a chip on the PCB.
Description of the Related Art
In electronic devices, printed circuit boards (PCBs) are used to mechanically support and electrically connect electronic components using conductive pathways, conductive traces (e.g. signal traces or ground traces) etched from metal sheets laminated onto a non-conductive core substrate. In recent years, an increased amount of input/output (I/O) connections for multi-functional or memory chips is required for a semiconductor chip package design. The impact of this will be pressure on printed circuit board (PCB) fabricators to minimize the width and the space of the conductive traces, or increase the number of layers on the PCB. The conductive traces used to transmit the signals corresponding to the same function need to be arranged and configured in the same manner on the PCB. For example, the conductive traces used to transmit the address/data bus of a memory need to be arranged and configured in parallel, and the spaces between the conductive traces are also small. However, the adjacent conductive traces on the PCB can result in a crosstalk problem, especially in high signal speed applications. Thus, the crosstalk problem can detrimentally affect the quality of a signal traveling on a conductive trace, thereby affecting the signal reception of the electronic component supported by the PCB.
Therefore, it is desirable to optimize the arrangement of the conductive traces for avoiding the crosstalk problem on a PCB of an electronic device.